I wonder how many can remember "Clay,s" we used to us it for most things it had a very strong smell when wet. It was said that it was dried London sewage but I do not know if that is true. There was also one called Three Nines but most of the old ones no longer re on the market.
From the 1919 copy of Grace's Guide:also 1938 &1945
Regarding source, probably correct, less squimish in years gone by. According to colloquial accounts, this was also the content of the original growbags from Fisons Levington.
Just shows memory has not gone completely yet, getting bad but on allotment this morning at 6.30 to fill water tank , no real rai yet . Thinking of giving up plot age 89 but it gives me something to do for exercise.
It must be a nightmare to garden in an area as dry as that. We've had some good soakings recently. I admire you for the effort.
I reckon my last bag of compost has a hint of dried sewage, a few pots of it has started growing a million and one tomato plants. I never planed them they must have been in the compost. I have put a couple in the poly to see what they come up like.